add function that writes TextureData to a PPM file

include/ACGL/OpenGL/Data/TextureDataPPMWriter.hh

+////////////////////////////////////////////////////////////////////////////////
+// Copyright (c) 2011, Computer Graphics Group RWTH Aachen University         //
+// All rights reserved.                                                       //
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef ACGL_OPENGL_DATA_TEXTUREDATAPPMWRITER_HH
+#define ACGL_OPENGL_DATA_TEXTUREDATAPPMWRITER_HH
+
+/**
+ * Helper function for writing the contents of a TextureData object into a PPM file.
+ * Expects 8 bit RGBA texture data (as can be provided by Texture::getImageData)
+ */
+
+#include <ACGL/ACGL.hh>
+#include <ACGL/OpenGL/Data/TextureData.hh>
+
+#include <string>
+
+namespace ACGL{
+namespace OpenGL{
+
+bool saveTextureDataToPPM(const ConstSharedTextureData& _textureData, const std::string& _filename);
+
+} // OpenGL
+} // ACGL
+
+#endif // ACGL_OPENGL_DATA_TEXTUREDATAPPMWRITER_HH

src/ACGL/OpenGL/Data/TextureDataPPMWriter.cc

+////////////////////////////////////////////////////////////////////////////////
+// Copyright (c) 2011, Computer Graphics Group RWTH Aachen University         //
+// All rights reserved.                                                       //
+////////////////////////////////////////////////////////////////////////////////
+
+#include <ACGL/OpenGL/Data/TextureDataPPMWriter.hh>
+#include <ACGL/OpenGL/Tools.hh>
+
+#include <fstream>
+
+using namespace ACGL;
+using namespace ACGL::OpenGL;
+using namespace ACGL::Utils;
+
+bool ACGL::OpenGL::saveTextureDataToPPM(const ConstSharedTextureData& _textureData, const std::string& _filename)
+{
+    std::ofstream outFileStream(_filename.c_str(), std::ios_base::out | std::ios_base::binary);
+
+    if(!outFileStream.good())
+    {
+        error() << "saveTextureDataToPPM: Could not open file " << _filename << std::endl;
+        return false;
+    }
+
+    // Use the binary-encoded RGB texture format
+    outFileStream << "P6" << std::endl;
+
+    // Width and height
+    outFileStream << _textureData->getWidth() << " " << _textureData->getHeight() << std::endl;
+
+    // Maximum value
+    uint_t maxValue;
+    if(_textureData->getType() == GL_UNSIGNED_BYTE)
+    {
+        maxValue = 255;
+    }
+    else
+    {
+        error() << "saveTextureDataToPPM: Unsupported data format" << std::endl;
+        return false;
+    }
+    outFileStream << maxValue;
+
+    // Single whitespace as a delimiter
+    outFileStream << "\n";
+
+    // Now, write the image data in binary format
+    for(uint_t y = _textureData->getHeight()-1; y > 0; --y)
+    {
+        for(uint_t x = 0; x < _textureData->getWidth(); ++x)
+        {
+            uint_t i = (y * _textureData->getWidth()) + x;
+
+            outFileStream.put(_textureData->getData()[(4*i + 0) * getGLTypeSize(_textureData->getType())]);
+            outFileStream.put(_textureData->getData()[(4*i + 1) * getGLTypeSize(_textureData->getType())]);
+            outFileStream.put(_textureData->getData()[(4*i + 2) * getGLTypeSize(_textureData->getType())]);
+        }
+    }
+
+    outFileStream.close();
+    return true;
+}